Calibrating the Diopter of Your Camera

Not all eyes are created equal. For those without “normal” 20/20 vision, this may be a problem when you look through a camera’s viewfinder—either optical or electronic. Your view into the camera might be blurry even when the camera’s lens is in focus. Because of this, your camera’s viewfinder likely has a diopter adjustment (some older cameras do not have diopter adjustments and require the addition of add-on viewfinder lenses to provide the same function).

The diopter adjustment allows you to customize the viewfinder so that you can see a clear, focused image inside the viewfinder without using eyeglasses or contact lenses to correct your vision.

I used to spend an inordinate amount of time at a fantastic camera store in San Diego. At least twice a day, a customer would come into the store and say, “My camera is broken… the viewfinder is all blurry.” Their camera was not broken; their diopter was out of adjustment.

How do you know your diopter needs to be adjusted?

The only way to tell if your diopter is accurately adjusted for your eyes is to look around the viewfinder symbology (grid, exposure information, focus points, digital data, etc.) and see if that is in focus. If the numbers, letters, and grid of your viewfinder are tack sharp and the image is not, the camera is out of focus or the autofocus is not working. If both the accurately “focused” image and the symbology are out of focus, you need to adjust your diopter.

How do you adjust your diopter?

Different viewfinders have different adjustments, but there is likely a small wheel or slide in close proximity to the viewfinder (sometimes labeled with a + and -) that allows you to adjust the view. There are different techniques for adjusting the diopter—feel free to share your own in the comments section below—but here is one that should work well:

1. Mount the camera. If you can, put the camera on a tripod and point it toward a bright scene with sharp straight edges and a fair amount of contrast—something that the camera should focus on easily.

2. Focus the camera. If it is an autofocus camera, activate the autofocus. If you have a manual focus camera, attempt to focus the image (using electronic focus indicators, if available).

3a. AUTOFOCUS CAMERA Are both the viewfinder image and symbology blurry to your eye? Then you need to adjust the diopter. Rotate the wheel or slide the slide until everything is sharp.

3b. MANUAL FOCUS CAMERA If the symbology is not sharp, you’ll need to adjust the diopter. Only then can you achieve accurate manual focus (unless you have electronic focus aids). Once the symbology is sharp following a diopter adjustment, adjust the manual focus as needed to ensure you can get the image in focus.

• When adjusting a camera diopter (or a diopter on a set of binoculars, for instance) you should adjust the diopter to make the image sharp, and keep adjusting until it goes back out of focus. Then, work back toward focus and stop. The reason to turn or slide past the focus is to ensure that you have made the adjustment far enough and not ended up short of true focus.

• Truth be told, if you are confident in your camera’s autofocus, you can likely do a quick and accurate diopter adjustment in the field by just looking at the viewfinder symbology and adjusting the wheel or slide until it is sharp.

Problems

If the camera is out of focus, you see a blurry image in the viewfinder. Then you either focus the camera using autofocus or manual focus and everything is sharp; but is it? What if you didn’t manually focus accurately? Or, worse, what if the autofocus is inoperative or erroneous?

If your camera’s viewfinder gives you sharp viewfinder symbology, but a blurry image, there are likely problems with the camera lens. If the image and symbology are crystal clear, but the image is slightly out of focus, you likely have a minor autofocus error. Verify this by switching to manual focus and see if you can achieve clear manual focus.

Check and re-check your diopter

Depending on the camera’s diopter adjustment design, the wheel or slide can easily get knocked out of position. So, if you peer into a blurry viewfinder, don’t panic—it might just be your diopter.

If your eyesight is such that a diopter adjustment cannot help you get a clear image in the viewfinder, some cameras can accommodate more extreme adjustment with add-on diopter accessories. Also, some cameras do not include diopter adjustments and the accessories exist to provide the same function as the adjustment dials and slides.

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5 months ago

Sue ZZaz

I could use some help. I dropped my canon eos t3i and now the viewfinder is blurry. My diopter wheel has no effect on the image in my viewfinder. When I turn on live view I can take a photo that is sharply focused but that isn't a good option for me. Somehow the mechanism that controls the diopter inside the camera is not functioning. Any suggestions on what I can do to fix it? I appreciate any and all advice! Thank you in advance!!!

Great article, although with mirrorless cameras, hit the MENU button first and adjust your diopter on the words and letters. MUCH faster and easier than trying to focus on an image that may or may not be perfectly focused.

I'm blind as a bat: 20/400+. As a working photographer and cinematographer in the '60s & '70s, I had to come up with a quick, accurate eyepiece adjustment (diopter adjustment) of the added rental equipment our crews often used. It's a method I still use. I found the easiest method - for both motion and still cameras - was to first remove the taking lens (assuming reflex viewing as with 35mm stills SLRs, most 16mm motion cameras, some 35mm motion cameras w/thru-the-lens viewfinding). With the lens removed, the ground glass or fresnel focusing screen is presented clearly, without distracting images. The screen's engraved crop marks, targets or other graphics are the perfect diopter-adjustment focusing reference. Absent those marks, the "grain" of the ground glass focusing screen is clearly visible - without distracting images. Adjust the eyepiece's diopter-correction lens for the sharpest edges on those focusing screen graphics and/or the sharpest image of the ground glass's "grain." You're now critically focused on the imaging plane of the ground glass. Remount the taking lens and start shooting. This method has worked quickly and accurately for me for more than 50 years.

Re: Astigmatism. I've not found a way to correct for my moderate astigmatism. But I've found I can get some relief by taking a break from the viewfinder for approx 25% of the time spent with my eye to the finder. That is, if shooting for an hour, I take a 15-minute break with my glasses on. That prevents the achy / quivery eye syndrome that I get because of astigmatism. If someone has another method to prevent that astigmatism-caused discomfort, I'm all ears!

To adjust the diopter settings on all of my digital cameras I use the white translucent body cap that came with one of them. (I can't remember which one) I remove the lens and put the rear lens cap on it. I put the white body cap on the camera and use the lines/engraved areas on the focus screen to dial in the proper diopter. By using this technique, I avoid potential AF and lens variability issues since what I am getting in focus is the focus screen. Before using the body cap, I used a bright white surface (computer screen, window, table top etc.) and threw it out of focus to set the diopter. Remember, you are trying to set the camera to properly focus on the focus screen (ironic use of words eh?) not an object at some distance.

You are very correct here. You are trying to focus on the focusing screen—not the image. This is much easier today with our busy viewfinders than in the past where focus screens were sometimes almost completely devoid of markings of any kind!

For me, I have found that focusing the camera on a small sign with lettering is the easiest way to adjust my diopter in the field. The lettering will usually have sharp edges that make it very easy to tell when it’s adjusted correctly. I use the camera’s auto focus and then, without moving the camera, adjust the diopter to get the sharpest view. Except in the most remote areas, small signs are everywhere.

I adjust the diopter on my Pentax K20D so the mini LCD panel in the viewfinder is in focus. I frequently check the autofocus using a LensAlign MKII Focus Calibration System pack. I can reset the calibration on the camera for any lens or for all lenses. Then by using either selective or center point autofocus my pictures are always in focus. I use depth-of-field camera settings 99% of the time so I have no worries.

That is good advice. Always check focus (and diopters) on things that you know are straight—usually man-made objects or writing on signs. Trying to verify focus or diopter settings on beautiful natural landscapes and objects can be tricky.

I would try adjusting the diopter without your glass and see if everything comes in focus. If not, attempt to adjust with your glass on. If that doesn't bring everything into focus, you may need to replace your diopter on your camera, if possible. I own a Nikon and wear glasses as well. I also went through the process of trail and error until everything was focused properly. Hope this helps you out.

I enjoyed reading your informative article, but if I might add couple of suggestions. First it would help to explain what a diopter is, since you are adjusting this. A diopter is an optical unit of measurement of how much light is bent (refracted) over a distance of 1 meter. By adjusting your diopter wheel in the + direction you are adding more "farsighted" correction. I just spent in the - direction is adding more "nearsighted" correction.

A good starting point for adjusting your you finders diopter we'll would be by looking at the card you get from your optometrist with your eyeglass prescription. A "Rule of Thumb," The first number in your prescription might indicate what direction to turn the wheel. If your eyeglass prescription for example starts with a +3.00, turn the wheel three clicks in the + direction. A prescription of -3.00, do the opposite. I don't want to get stuck in the weeds with astigmatism correction and your glasses but this is just a starting point

I struggle with manual focus viewfinder situations, I always have because of extreme short-sightedness, and my prescription "going off" when I was younger and wearing glasses. I wasted bucketloads of film this way. These days, I wear multi focal contact lenses, and they make manual focus with older film cameras almost impossible - when you wear them, your eye uses different parts of the contact lens to focus depending on the distance, and it happens automatically and you don't know you're doing it. When manually focusing on a DSLR, using a live view screen, it's not a problem, because the screen itself is what your eye is focusing on, and it's a flat plane. It can almost be that way with a waist level viewfinder as well, within limitations.

It's a pity that some cameras (my 5DSR included), don't have a scale or a readout for the diopter adjustment - it works brilliantly, but if it could give me a value, I could translate that to other uses, such as accurately buying focusing screens for my Hasselblad. This is a service that optometrists should provide, it could be an earner for them - but when you ask, they look at you with a blank stare.

I used many an older focus system back in film days. What I found about eye doctors was that when you asked them what diopter you need to focus your camera they were unable to tell you. In fact they seemed at a loss when it came to talking about camera lenses. I never understood this and am currently glad that my Niko D7200 as well as my D5200 (backup gear) have diopter adjustments now that I need them, especially since I had my cataracts removed.

Are there any solutions for fixing astigmatism? I am experimenting with wearing astigmatism-correcting contact lenses, but it is an imperfect solution. I would like a custom viewfinder for my Canon 5DM3 and 5DSR that provide the astigmatism correction of my spectacles. Anyplace I could get a lens custom-ground, for example?

My local search came up empty. There are definitely no products that we sell that would correct a viewfinder for an astigmatism. I then did some digging around the internet and found a few interesting articles, but no magic solution.

Your best solution will be to wear your glasses while shooting. It may be helpful to remove any rubber eyecup from the viewfinder to allow your glasses to get closer to the camera...but, be careful of scratching your lenses!

Yes a lens can be lmade- I worked for a glass lab that did any kind of lens anyone needed however, that company is out of business. Look for a lab- not a retail store, and go in and see if they will make you a lens (what ever size you need, toyour rx.This is not a big deal- It should even be that costly as it is a single vision lens(no bifocal). Remember - Look for a local lab, not a lenscrafters, or sears, or walmart but a "Lab". I only did this for 30 years and I know it is available from a lab. We even made telescope lenses, diving lenses etc..

If I might suggest a simple alternative to having an optical lab custom-grind a lens to fit your viewfinder (always possible provided that cost is no object). Daily disposable soft contact lenses for astigmatism is a viable method for photographers to correct their astigmatism, while they are out on a photo shoot. These lenses are useful for people who have never worn contact lenses, and don't want to wear them on a daily basis. They are very comfortable and most people adapt to them immediately. You wear them all-day long. At the end of the day, you throw them away. You wear them as much or as little as you want to. No solutions, no care and upkeep. Keep several pairs in your photo bag, to wear when needed. They are available in 30 and 90 pack quantities. Daily disposable contact lenses are available with a prescription from most Optometrists.

I have made a custom diopter for my Bronica. I cut a section of plastic lens from an old pair of prescription reading glasses using a hacksaw blade and final shaping with sandpaper. I then insertedthe lens into the eyepiece chamber that is accessible by removing a few screws. The result is that I am able to use the camera without my glasses. The same can be done for cameras that have screw on or slip on eyepiece accessories.

I had a lens ground and placed into an empty filter holder for my telescope, to correct astigmatism. Of course it was round but since the use polycarbonate I don't see why one couldn't grind it down to an appropriate size (and have it ground for a certain diopter, of course).